Method of maintaining electric-spark-plug insulators free from conducting-carbon.



- active elements do not CHARLES KNOX HAEDING, OF CHICAGO, ILLINOIb.

METHOD OF MAINTAINING ELECTRIC-SPARK-PLUG INSUI'ATORS FREE 1150M CONDUCT- ING- CARBON.

No Drawing.

To all whom it may concern Be it known that I, Crrumns Knox HARD- ING, a citizen of the United States, and a resident of lVoodlawn, city of Chicago, county of Cook, State of Illinois, have invented certain new and useful Improvements in Methods of Maintaining Electric- Spark-Plug Insulators Free from Conducting-Carbon.

My invention is an improved process or method of operation to insure the continuous and uninterrupted operation of electric ignition terminals and insulators within the explosion chambers of internal combustion engines supplied with a gaseous mixture of hydrocarbon and air, and employs catalytic fiameless combustion of part of the mixture to produce heat to keep the insulator hot for a relatively long time in advance of the exact moment when the mixture is inflamed and exploded by the passage of the electric spark. The fiamele'ss combustion is produced by passing the combustible mixture in contact with a suitable catalytic, n0n-igniting, oxidizing agent that will produce catalytic combustion without inflaming or exploding the mixture.

In carrying out my process the catalytic agent is preferably placed in close heat transmitting proximity to the electric insulator so that enough of the heat liberated maybe conveyed, conducted or radiated to it to keep the insulator sufiiciently hot during a relatively long period of time, and during some part of thecycle of the engine when the explosive mixture contains free air, or unburned oxygen, so that the surface carbon is completely burned oil and the heated portion of the insulator kept perfectly clean and its electrical insulation properties unimpaired by deposits or con ducting carbon.

In carrying out my process, any suitable catalytic material known to those skilled in the art may be employed that will produceand maintain catalytic combustion. Structures of palladium begin to act on gaseous mixtures containing hydrogen at temperatures below zero. Platinum structures have to be initially heated to one hundred degrees F. Non-metallic structures of radio roduce noticeable oxidization until the com ustible mixture is heated to over six hundred degrees F.

In a spark plug it is only necessary to Specification of Letters Patent.

Application filed November 11, 1916. Serial No. 130,896.

have the fiameless combustion start a little time in advance and at a few hundred degrees lower temperature than the inflaming temperature of the mixture. Any of the metals of the platinum group or the oxids of radio active elements, alone or in combination, may be used without exceeding the scope of this invention.

For further description of apparatus and )rocesses employing fiameless catalytic comustion, reference may be had to my prior United States Patents Nos. 803,534, October 31, 1905; 969,368. September 6, 1910; 1,067,983, July 22, 1913, and 1,198,542 for structures for producing flameless catalytic combustion, issued September 19, 1916.

Having now described my invention, What I claim is, .7

1. The improved method ofv preventing the accumulation of conducting carbon on the surfaces of electrical insulators of spark plugs for the electrical ignition of explosive mixtures of hydrocarbons in internal combustion engines which consists in causing part of the mixture to pass in contact with a non-igniting, oxidizing catalytic agent placed in heat transmitting proximity to the insulator, and heating the insulator and catalytic agent by the flameless catalytic combustion of part of the mixture during a relatively long period of time in the presence of oxygen or the unexploded mixture preceding the instant at which the Whole mixture is exploded by the electric spark and thereby burning conducting carbon from the heated insulator.

2. As an improvement in the art of electrical ignition for internal combustion e11- gines the process of burning electrically conducting carbon from the interiorly exposed surfaces of electric spark plug insulators which consists in heating the surface of the insulators in contact with a portion of the explosive fuel-air mixture by fiamcless' catalytic combustion of part of said mixture at a time before the Whole mixture is exploded by the electric ignition at which time there is sufiicicnt free oxygen in the mixture to oxidize and burn off conducting carbon deposits from the hot insulator.

3. As an improvement in the art of electric ignition for internal combustion engines the process of burning electrically conducting carbon from the interiorly exposed surfaces of electric spark plug insulators 'which consists in heating said insulating there is sufficient free oxygen in the air-fuel surface to a high temperature in the presmixture to burn off conducting carbon de- 11; ence of oxygen of the unexploded combustiposits from the hot surface of the insulator. ble fuel-air mixture and. heatin said in- In testimony whereof, I have signed m sulator by catalyticallyproduce flameless name to this specification this the 9th day Combustion of part of said mixture for a of November, A. D; 1916. period of time before the Whole mixture is exploded by the electric spark and when CHARLES KNOX HARDING. 

